Many kinds of windows and doors are typically provided with grills to enhance the appearance thereof. These grills are usually removable, and various types of fasteners are used to attach the grills to the window or door frame. In order to avoid impairing the appearance of the grill, attempts have been made to develop concealed fasteners.
For example, U.S. Pat. No. 4,644,721 discloses a concealed type clip, which is used to secure a grill to a window or door frame. However, this particular arrangement requires the grill bar to be provided with specially designed slots to allow specially designed fastening clips to be cammed into the slots.